Winches are used in many applications. Normally, the winch itself will be rigidly mounted on a first object, and a cable or wire of some desired length will be secured to the winch and extend to connect to a second object. By rotating the drum on the winch, the cable can be payed out or taken up on the drum as desired.
In some applications, the objects can move suddenly relative to each other, causing a shock loading in the cable. Such a shock loading can be very detrimental in terms of the service life of the equipment, and even its structural integrity. One example of such an application is a winch mounted on a fixed offshore platform to moor a supply boat. The free end of the cable from the winch is attached to a supply boat, frequently in rough seas. Since it is absolutely essential to prevent the supply boat from hitting the platform, the boat is moored downwind from the platform and the prevailing winds and current act to move the boat away from the platform, inducing a tension force in the cable. Due to wave and wind action, the cable is frequently subjected to a shock loading as the boat motion is brought up short by the cable.
In the past, compensators have been used which are actually incorporated into the cable extending between a winch and an object. Such compensators are typically hydropneumatic in operation and are therefore "active" systems which require a continuous supply of pressurized air or fluid for operation.
A need exists for an improved compensator for use in reducing shock loading on a cable taken in and payed out from a winch. Such a compensator should be reliable and preferably not require a continuous supply of high pressure hydraulic fluid or air.